20mm SS pin to go inside of the wreath - combination replacing a skull found in historical SS visor caps. 
 
Note on SS pin: while it's possible to source an SS pin elsewhere, it's unlikely you'll find such an exact match which I got made to match perfectly what was used in the TV series (20 mm diameter, flat, double circle around). 
 
Note on wreath: Wreaths can be purchased anywhere, as these are standard Wehmachtr cap wreaths.